__ sale (3)
'sale' is the definition.
(public sale)
This is the entire clue.
(Other definitions for auction that I've seen before include "Public sale to the highest bidder" , "Competitive sale" , "Offer to bidders" , "Caution about method of sale" , "Selling" .)
(Other definitions for tag that I've seen before include "Children's chasing game" , "Label (to attach)" , "Identity badge" , "Name" , "Refrain" .)